Inexpensive heater core replacements can be found at online vehicle replacement parts websites, such as Auto Parts Warehouse and Parts Train. As of 2014, heater cores are typically either aluminum or copper, although aluminum is most commonly used, according to Auto Parts Warehouse.
Professional auto parts warehouses carry heater cores from all major manufacturers and are often covered by manufacturer's warranties. High-efficiency heating cores are recommended by professionals, because operating costs of heating systems are higher than the original purchase price. Heater cores are typically cleaned during routine maintenance, but full replacement is normally needed around five years or 50,000 miles, according to Auto Parts Warehouse.